void MultiColumnFragmentainerGroup::collectLayerFragments(DeprecatedPaintLayerFragments& fragments, const LayoutRect& layerBoundingBox, const LayoutRect& dirtyRect) const
{
// |layerBoundingBox| is in the flow thread coordinate space, relative to the top/left edge of
// the flow thread, but note that it has been converted with respect to writing mode (so that
// it's visual/physical in that sense).
//
// |dirtyRect| is visual, relative to the multicol container.
//
// Then there's the output from this method - the stuff we put into the list of fragments. The
// fragment.paginationOffset point is the actual visual translation required to get from a
// location in the flow thread to a location in a given column. The fragment.paginationClip
// rectangle, on the other hand, is in flow thread coordinates, but otherwise completely
// physical in terms of writing mode.
//
// All other rectangles in this method are sized physically, and the inline direction coordinate
// is physical too, but the block direction coordinate is "logical top". This is the same as
// e.g. LayoutBox::frameRect(). These rectangles also pretend that there's only one long column,
// i.e. they are for the flow thread.
LayoutMultiColumnFlowThread* flowThread = m_columnSet.multiColumnFlowThread();
bool isHorizontalWritingMode = m_columnSet.isHorizontalWritingMode();
// Put the layer bounds into flow thread-local coordinates by flipping it first. Since we're in
// a layoutObject, most rectangles are represented this way.
LayoutRect layerBoundsInFlowThread(layerBoundingBox);
flowThread->flipForWritingMode(layerBoundsInFlowThread);
// Now we can compare with the flow thread portions owned by each column. First let's
// see if the rect intersects our flow thread portion at all.
LayoutRect clippedRect(layerBoundsInFlowThread);
clippedRect.intersect(m_columnSet.flowThreadPortionOverflowRect());
if (clippedRect.isEmpty())
return;
// Now we know we intersect at least one column. Let's figure out the logical top and logical
// bottom of the area we're checking.
LayoutUnit layerLogicalTop = isHorizontalWritingMode ? layerBoundsInFlowThread.y() : layerBoundsInFlowThread.x();
LayoutUnit layerLogicalBottom = (isHorizontalWritingMode ? layerBoundsInFlowThread.maxY() : layerBoundsInFlowThread.maxX()) - 1;
// Figure out the start and end columns and only check within that range so that we don't walk the
// entire column row.
unsigned startColumn = columnIndexAtOffset(layerLogicalTop);
unsigned endColumn = columnIndexAtOffset(layerLogicalBottom);
LayoutUnit colLogicalWidth = m_columnSet.pageLogicalWidth();
LayoutUnit colGap = m_columnSet.columnGap();
unsigned colCount = actualColumnCount();
bool progressionIsInline = flowThread->progressionIsInline();
bool leftToRight = m_columnSet.style()->isLeftToRightDirection();
LayoutUnit initialBlockOffset = m_columnSet.logicalTop() + logicalTop() - flowThread->logicalTop();
for (unsigned i = startColumn; i <= endColumn; i++) {
// Get the portion of the flow thread that corresponds to this column.
LayoutRect flowThreadPortion = flowThreadPortionRectAt(i);
// Now get the overflow rect that corresponds to the column.
LayoutRect flowThreadOverflowPortion = flowThreadPortionOverflowRect(flowThreadPortion, i, colCount, colGap);
// In order to create a fragment we must intersect the portion painted by this column.
LayoutRect clippedRect(layerBoundsInFlowThread);
clippedRect.intersect(flowThreadOverflowPortion);
if (clippedRect.isEmpty())
continue;
// We also need to intersect the dirty rect. We have to apply a translation and shift based off
// our column index.
LayoutPoint translationOffset;
LayoutUnit inlineOffset = progressionIsInline ? i * (colLogicalWidth + colGap) : LayoutUnit();
if (!leftToRight)
inlineOffset = -inlineOffset;
translationOffset.setX(inlineOffset);
LayoutUnit blockOffset;
if (progressionIsInline) {
blockOffset = initialBlockOffset + (isHorizontalWritingMode ? -flowThreadPortion.y() : -flowThreadPortion.x());
} else {
// Column gap can apply in the block direction for page fragmentainers.
// There is currently no spec which calls for column-gap to apply
// for page fragmentainers at all, but it's applied here for compatibility
// with the old multicolumn implementation.
blockOffset = i * colGap;
}
if (isFlippedBlocksWritingMode(m_columnSet.style()->writingMode()))
blockOffset = -blockOffset;
translationOffset.setY(blockOffset);
if (!isHorizontalWritingMode)
translationOffset = translationOffset.transposedPoint();
// Shift the dirty rect to be in flow thread coordinates with this translation applied.
LayoutRect translatedDirtyRect(dirtyRect);
translatedDirtyRect.moveBy(-translationOffset);
// See if we intersect the dirty rect.
clippedRect = layerBoundingBox;
clippedRect.intersect(translatedDirtyRect);
if (clippedRect.isEmpty())
continue;
// Something does need to paint in this column. Make a fragment now and supply the physical translation
// offset and the clip rect for the column with that offset applied.
DeprecatedPaintLayerFragment fragment;
fragment.paginationOffset = translationOffset;
LayoutRect flippedFlowThreadOverflowPortion(flowThreadOverflowPortion);
// Flip it into more a physical (DeprecatedPaintLayer-style) rectangle.
flowThread->flipForWritingMode(flippedFlowThreadOverflowPortion);
fragment.paginationClip = flippedFlowThreadOverflowPortion;
fragments.append(fragment);
}
}
void DeprecatedPaintLayerPainter::paintLayerWithTransform(GraphicsContext* context, const DeprecatedPaintLayerPaintingInfo& paintingInfo, PaintLayerFlags paintFlags)
{
TransformationMatrix layerTransform = m_paintLayer.renderableTransform(paintingInfo.globalPaintFlags());
// If the transform can't be inverted, then don't paint anything.
if (!layerTransform.isInvertible())
return;
// FIXME: We should make sure that we don't walk past paintingInfo.rootLayer here.
// m_paintLayer may be the "root", and then we should avoid looking at its parent.
DeprecatedPaintLayer* parentLayer = m_paintLayer.parent();
ClipRect ancestorBackgroundClipRect;
if (parentLayer) {
// Calculate the clip rectangle that the ancestors establish.
ClipRectsContext clipRectsContext(paintingInfo.rootLayer, (paintFlags & PaintLayerUncachedClipRects) ? UncachedClipRects : PaintingClipRects, IgnoreOverlayScrollbarSize);
if (shouldRespectOverflowClip(paintFlags, m_paintLayer.layoutObject()) == IgnoreOverflowClip)
clipRectsContext.setIgnoreOverflowClip();
ancestorBackgroundClipRect = m_paintLayer.clipper().backgroundClipRect(clipRectsContext);
}
DeprecatedPaintLayer* paginationLayer = m_paintLayer.enclosingPaginationLayer();
DeprecatedPaintLayerFragments fragments;
if (paginationLayer) {
// FIXME: This is a mess. Look closely at this code and the code in Layer and fix any
// issues in it & refactor to make it obvious from code structure what it does and that it's
// correct.
ClipRectsCacheSlot cacheSlot = (paintFlags & PaintLayerUncachedClipRects) ? UncachedClipRects : PaintingClipRects;
ShouldRespectOverflowClip respectOverflowClip = shouldRespectOverflowClip(paintFlags, m_paintLayer.layoutObject());
// Calculate the transformed bounding box in the current coordinate space, to figure out
// which fragmentainers (e.g. columns) we need to visit.
LayoutRect transformedExtent = DeprecatedPaintLayer::transparencyClipBox(&m_paintLayer, paginationLayer, DeprecatedPaintLayer::PaintingTransparencyClipBox, DeprecatedPaintLayer::RootOfTransparencyClipBox, paintingInfo.globalPaintFlags());
// FIXME: we don't check if paginationLayer is within paintingInfo.rootLayer here.
paginationLayer->collectFragments(fragments, paintingInfo.rootLayer, paintingInfo.paintDirtyRect, cacheSlot, IgnoreOverlayScrollbarSize, respectOverflowClip, 0, paintingInfo.subPixelAccumulation, &transformedExtent);
} else {
// We don't need to collect any fragments in the regular way here. We have already
// calculated a clip rectangle for the ancestry if it was needed, and clipping this
// layer is something that can be done further down the path, when the transform has
// been applied.
DeprecatedPaintLayerFragment fragment;
fragment.backgroundRect = paintingInfo.paintDirtyRect;
fragments.append(fragment);
}
bool needsScope = fragments.size() > 1;
for (const auto& fragment : fragments) {
Optional<ScopeRecorder> scopeRecorder;
if (needsScope)
scopeRecorder.emplace(*context);
Optional<LayerClipRecorder> clipRecorder;
if (parentLayer) {
ClipRect clipRectForFragment(ancestorBackgroundClipRect);
clipRectForFragment.moveBy(fragment.paginationOffset);
clipRectForFragment.intersect(fragment.backgroundRect);
if (clipRectForFragment.isEmpty())
continue;
if (needsToClip(paintingInfo, clipRectForFragment))
clipRecorder.emplace(*context, *parentLayer->layoutObject(), DisplayItem::ClipLayerParent, clipRectForFragment, &paintingInfo, fragment.paginationOffset, paintFlags);
}
paintFragmentByApplyingTransform(context, paintingInfo, paintFlags, fragment.paginationOffset);
}
}
